Document Detail

Enhanced degradation of tryptophan in patients on hemodialysis.
MedLine Citation:
PMID:  21084050     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Hemodialysis patients often present with increased concentrations of tryptophan catabolites perhaps related to an enhanced activity of tryptophan-degrading enzyme indoleamine 2,3-dioxygenase (IDO) that is inducible by pro-inflammatory stimuli. The often chronic inflammation and immune activation status in dialysis patients may accelerate tryptophan degradation, which could influence patients' psychological performance.
PATIENTS AND METHODS: In this study, plasma concentrations of kynurenine and tryptophan were determined by HPLC in 75 dialysis patients, aged 65.3 ± 15.0 years. Forty patients were female, 35 male; 21 (28%) had diabetes mellitus Type 1 or 2 and 32 (43%) suffered from sleep disturbances and/or depression. Their dialysis vintage was 4.26 ± 4.72 years. HPLC results were compared to concentrations obtained from 40 healthy blood donors, to immune activation marker neopterin, and to psychological test results based on INTERMED scores.
RESULTS: Compared to those in healthy controls, tryptophan concentrations were decreased in patients. Neopterin, kynurenine and the kynurenine to tryptophan ratio (kyn/trp, an index of tryptophan degradation) were increased in patients (all p < 0.01). Kyn/trp correlated with neopterin concentrations (rs = 0.393, p < 0.01). INTERMED scores were 21.0 + 8.4 and slightly higher in females (U = -1.831, p < 0.07); they correlated with tryptophan concentrations (rs = -0.227, p < 0.05) but with no other parameter studied. Data point to a possible relationship between tryptophan metabolic disturbances and psychologic presentation of patients, although only a rather weak relationship was found.
CONCLUSION: We conclude that tryptophan degradation is increased in dialysis patients. The association with increased neopterin concentrations indicates activated IDO.
P Koenig; C Nagl; G Neurauter; H Schennach; G Brandacher; D Fuchs
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Clinical nephrology     Volume:  74     ISSN:  0301-0430     ISO Abbreviation:  Clin. Nephrol.     Publication Date:  2010 Dec 
Date Detail:
Created Date:  2010-11-18     Completed Date:  2011-01-21     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0364441     Medline TA:  Clin Nephrol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  465-70     Citation Subset:  IM    
Department of Internal Medicine, Innsbruck Medical University, Austria.
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MeSH Terms
Aged, 80 and over
Biological Markers / blood
Case-Control Studies
Chromatography, High Pressure Liquid
Enzyme Activation
Indoleamine-Pyrrole 2,3,-Dioxygenase / metabolism
Kynurenine / blood
Middle Aged
Neopterin / blood
Quality of Life
Renal Dialysis*
Treatment Outcome
Tryptophan / blood*
Uremia / blood,  psychology,  therapy*
Young Adult
Reg. No./Substance:
0/Biological Markers; 343-65-7/Kynurenine; 670-65-5/Neopterin; 73-22-3/Tryptophan; EC 2,3,-Dioxygenase

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